Predictors of 25-hydroxyvitamin D and its association with risk factors for prostate cancer: evidence from the prostate testing for cancer and treatment study

Active monitoring, radical prostatectomy and radical radiotherapy in PSA-detected clinically localised prostate cancer: the ProtecT three-arm RCT

BACKGROUND

Prostate cancer is the most common cancer among men in the UK. Prostate-specific antigen testing followed by biopsy leads to overdetection, overtreatment as well as undertreatment of the disease. Evidence of treatment effectiveness has lacked because of the paucity of randomised controlled trials comparing conventional treatments.

OBJECTIVES

To evaluate the effectiveness of conventional treatments for localised prostate cancer (active monitoring, radical prostatectomy and radical radiotherapy) in men aged 50-69 years.

DESIGN

A prospective, multicentre prostate-specific antigen testing programme followed by a randomised trial of treatment, with a comprehensive cohort follow-up.

SETTING

Prostate-specific antigen testing in primary care and treatment in nine urology departments in the UK.

PARTICIPANTS

Between 2001 and 2009, 228,966 men aged 50-69 years received an invitation to attend an appointment for information about the Prostate testing for cancer and Treatment (ProtecT) study and a prostate-specific antigen test; 82,429 men were tested, 2664 were diagnosed with localised prostate cancer, 1643 agreed to randomisation to active monitoring (n = 545), radical prostatectomy (n = 553) or radical radiotherapy (n = 545) and 997 chose a treatment.

INTERVENTIONS

The interventions were active monitoring, radical prostatectomy and radical radiotherapy.

TRIAL PRIMARY OUTCOME MEASURE

Definite or probable disease-specific mortality at the 10-year median follow-up in randomised participants.

SECONDARY OUTCOME MEASURES

Overall mortality, metastases, disease progression, treatment complications, resource utilisation and patient-reported outcomes.

RESULTS

There were no statistically significant differences between the groups for 17 prostate cancer-specific (p = 0.48) and 169 all-cause (p = 0.87) deaths. Eight men died of prostate cancer in the active monitoring group (1.5 per 1000 person-years, 95% confidence interval 0.7 to 3.0); five died of prostate cancer in the radical prostatectomy group (0.9 per 1000 person-years, 95% confidence interval 0.4 to 2.2 per 1000 person years) and four died of prostate cancer in the radical radiotherapy group (0.7 per 1000 person-years, 95% confidence interval 0.3 to 2.0 per 1000 person years). More men developed metastases in the active monitoring group than in the radical prostatectomy and radical radiotherapy groups: active monitoring, n = 33 (6.3 per 1000 person-years, 95% confidence interval 4.5 to 8.8); radical prostatectomy, n = 13 (2.4 per 1000 person-years, 95% confidence interval 1.4 to 4.2 per 1000 person years); and radical radiotherapy, n = 16 (3.0 per 1000 person-years, 95% confidence interval 1.9 to 4.9 per 1000 person-years; p = 0.004). There were higher rates of disease progression in the active monitoring group than in the radical prostatectomy and radical radiotherapy groups: active monitoring (n = 112; 22.9 per 1000 person-years, 95% confidence interval 19.0 to 27.5 per 1000 person years); radical prostatectomy (n = 46; 8.9 per 1000 person-years, 95% confidence interval 6.7 to 11.9 per 1000 person-years); and radical radiotherapy (n = 46; 9.0 per 1000 person-years, 95% confidence interval 6.7 to 12.0 per 1000 person years; p < 0.001). Radical prostatectomy had the greatest impact on sexual function/urinary continence and remained worse than radical radiotherapy and active monitoring. Radical radiotherapy's impact on sexual function was greatest at 6 months, but recovered somewhat in the majority of participants. Sexual and urinary function gradually declined in the active monitoring group. Bowel function was worse with radical radiotherapy at 6 months, but it recovered with the exception of bloody stools. Urinary voiding and nocturia worsened in the radical radiotherapy group at 6 months but recovered. Condition-specific quality-of-life effects mirrored functional changes. No differences in anxiety/depression or generic or cancer-related quality of life were found. At the National Institute for Health and Care Excellence threshold of £20,000 per quality-adjusted life-year, the probabilities that each arm was the most cost-effective option were 58% (radical radiotherapy), 32% (active monitoring) and 10% (radical prostatectomy).

LIMITATIONS

A single prostate-specific antigen test and transrectal ultrasound biopsies were used. There were very few non-white men in the trial. The majority of men had low- and intermediate-risk disease. Longer follow-up is needed.

CONCLUSIONS

At a median follow-up point of 10 years, prostate cancer-specific mortality was low, irrespective of the assigned treatment. Radical prostatectomy and radical radiotherapy reduced disease progression and metastases, but with side effects. Further work is needed to follow up participants at a median of 15 years.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN20141297.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 37. See the National Institute for Health Research Journals Library website for further project information.

The Elderly-Nutrient Rich Food Score Is Associated With Biochemical Markers of Nutritional Status in European Older Adults

Background: In order to prevent age-related degenerative diseases in the aging population, their diets should be nutrient dense. For this purpose, the Elderly-Nutrient rich food (E-NRF7.3) score has been developed to assess nutrient density of diets by capturing dietary reference values for older adults. To demonstrate its practical importance such score should be validated against markers of nutritional status and health. Objective: The objective of this study was to examine the association between the E-NRF7.3 score and markers of nutritional status and inflammation. Design: This study was carried out in a sample of the NU-AGE study including 242 Dutch and 210 Polish men and women, aged 65-79 years. Dietary intake was assessed by means of 7-day food records and structured questionnaires collected data on supplement use, lifestyle, and socio-economic information. Baseline measurements included anthropometrics, physical and cognitive function tests, and a fasting venipuncture. E-NRF7.3 scores were calculated to estimate nutrient density of foods and the diet. Associations between the E-NRF7.3 scores and micronutrient status of vitamin D, folate, vitamin B12, homocysteine, and c-reactive protein (CRP) were examined using linear regression analysis while adjusting for confounders. Results: Each one unit increase in E-NRF7.3 score was associated with a 2.2% increase in serum folate in Dutch and 1.6% increase in Polish participants in the fully adjusted models (both p < 0.01). Each one unit increase in E-NRF7.3 was significantly associated with a 1.5% decrease in homocysteine levels in Dutch participants (p < 0.01), whereas, a 0.9% increase in vitamin B12 levels was observed in Polish participants only (p < 0.01). Higher E-NRF7.3 scores were not associated with vitamin D or CRP levels. Adjustment for potential confounders did not substantially alter these results. Discussion: The E-NRF7.3 was developed to reflect dietary intake of relevant nutrients for older adults. Its association with markers of nutritional status could be confirmed for folate (both populations), vitamin B12 (Poland only), and homocysteine (the Netherlands only). There was no association with vitamin D and CRP. To further demonstrate its validity and practical implication, future studies should include a wider range of nutritional status makers, health outcomes, and inflammation markers.

The effect of sunscreen on vitamin D: a review

BACKGROUND

Sunscreen use can prevent skin cancer, but there are concerns that it may increase the risk of vitamin D deficiency.

OBJECTIVES

We aimed to review the literature to investigate associations between sunscreen use and vitamin D₃ or 25 hydroxyvitamin D [25(OH)D] concentration.

METHODS

We systematically reviewed the literature following the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. We identified manuscripts published in English between 1970 and 21 November 2017. Eligible studies were experimental [using an artificial ultraviolet radiation (UVR) source], field trials or observational studies. The results of each of the experimental studies and field trials are described in detail. Two authors extracted information from observational studies, and applied quality scoring criteria that were developed specifically for this question. These have been synthesized qualitatively.

RESULTS

We included four experimental studies, three field trials (two were randomized controlled trials) and 69 observational studies. In the experimental studies sunscreen use considerably abrogated the vitamin D₃ or 25(OH)D production induced by exposure to artificially generated UVR. The randomized controlled field trials found no effect of daily sunscreen application, but the sunscreens used had moderate protection [sun protection factor SPF) ~16]. The observational studies mostly found no association or that self-reported sunscreen use was associated with higher 25(OH)D concentration.

CONCLUSIONS

There is little evidence that sunscreen decreases 25(OH)D concentration when used in real-life settings, suggesting that concerns about vitamin D should not negate skin cancer prevention advice. However, there have been no trials of the high-SPF sunscreens that are now widely recommended. What's already known about this topic? Previous experimental studies suggest that sunscreen can block vitamin D production in the skin but use artificially generated ultraviolet radiation with a spectral output unlike that seen in terrestrial sunlight. Nonsystematic reviews of observational studies suggest that use in real life does not cause vitamin D deficiency. What does this study add? This study systematically reviewed all experimental studies, field trials and observational studies for the first time. While the experimental studies support the theoretical risk that sunscreen use may affect vitamin D, the weight of evidence from field trials and observational studies suggests that the risk is low. We highlight the lack of adequate evidence regarding use of the very high sun protection factor sunscreens that are now recommended and widely used.

Sex consideration in diet-biomarker-related indices: a systematic review

OBJECTIVE

An index of biomarkers derived from dietary factors (diet-biomarker-related index) identifies foods and nutrients that encompass physiological potentials and provides scientific evidence for dietary patterns that increase the risk of disease associated with specific biomarkers. Although men and women have different dietary patterns and physiological characteristics, sex is not often considered when investigators develop a diet-biomarker-related index. We aimed to review whether epidemiological studies developed diet-biomarker-related indices in a sex-specific way.

DESIGN

We systematically searched for epidemiological studies that developed diet-biomarker-related indices, including (i) biomarker prediction indices that include dietary factors as explanatory variables and (ii) dietary patterns to explain biomarker variations, in the PubMed and EMBASE databases. We qualitatively reviewed the sex consideration in index development.

RESULTS

We identified seventy-nine studies that developed a diet-biomarker-related index. We found that fifty-four studies included both men and women. Of these fifty-four studies, twenty-nine (53·7 %) did not consider sex, eleven (20·3 %) included sex in the development model, seven (13·0 %) considered sex but did not include sex in the development model, and seven (13·0 %) derived a diet-biomarker-related index for men and women separately. A list of selected dietary factors that explained levels of biomarkers generally differed by sex in the studies that developed a diet-biomarker-related index in a sex-specific way.

CONCLUSIONS

Most studies that included both men and women did not develop the diet-biomarker-related index in a sex-specific way. Further research is needed to identify whether a sex-specific diet-biomarker-related index is more predictive of the disease of interest than an index without sex consideration.

Determinants of Plasma 25-Hydroxyvitamin D Concentrations among Breast Cancer Survivors in Korea

We identified demographic, lifestyle, and clinical factors associated with vitamin D status among breast cancer survivors. The vitamin D prediction model may be a useful surrogate of circulating 25-hydroxvitamin D (25(OH)D) concentrations when this measure was not available. We included a total of 216 Korean breast cancer survivors aged 21–79 years who had been diagnosed with stage I to III primary breast cancer and had breast cancer surgery at least 6 months before enrolment. We used linear and logistic regressions to identify determinants for the plasma 25(OH)D concentrations and vitamin D insufficiency (plasma 25(OH)D concentration < 50 nmol/L). We observed that 48.85% of breast cancer survivors had a plasma 25(OH)D concentration less than 50 nmol/L. We identified the following determinants for plasma 25(OH)D concentrations: time since diagnosis (β = −0.005 for 1 month increment), supplementary vitamin D intake (β = 0.06 for 10 μg/day increment), season of the blood draw (β = 0.35 for summer; β = 0.32 for fall; β = 0.26 for winter vs. spring), smoking status (β = 0.28 for former vs. never), use of any supplement (β = −0.35 for non-use vs. use), and the parity number (β = −0.30 for three or more vs. one) were associated with the plasma 25(OH)D concentrations. In addition to the aforementioned variables, body mass index (BMI) was associated with the prevalence of vitamin D insufficiency. We identified the determinants for the plasma 25(OH)D concentrations among Korean breast cancer survivors. Future studies are needed to investigate the role of vitamin D in the progression of breast cancer among Korean breast cancer survivors.

Circulating vitamin D concentration and risk of prostate cancer: a dose-response meta-analysis of prospective studies

Background

Though many studies have been performed to elucidate the association between circulating vitamin D and prostate cancer, no conclusive result is available. We carried out a dose-response meta-analysis to quantitatively examine the association of circulating 25-hydroxyvitamin D (25[OH]D) concentration with prostate cancer.

Methods

Only prospective studies examining the associations of circulating 25[OH]D concentration with prostate cancer were eligible for the meta-analysis. A random-effect meta-analysis was done first, to calculate the summary relative risk (RR) and 95% confidence intervals (CIs) comparing the higher concentration with the lower concentration of 25[OH]D. A dose-response meta-analysis using random-effects model was then carried out to evaluate the nonlinearity and calculate the summary RR caused per 10 ng/mL increment.

Results

Nineteen prospective cohort or nested case-control studies were included. Higher 25[OH]D concentration was significantly correlated with elevated risk of prostate cancer (RR =1.15, 95% CI 1.06-1.24). No nonlinear relationship was found between 25[OH]D concentration and risk of prostate cancer (P=0.654). Dose-response meta-analysis showed that the summary RR caused per 10 ng/mL increment in circulating 25[OH]D concentration was 1.04 (95% CI 1.02-1.06). Subgroup analysis also found a modest dose-response relationship. Funnel plot and Egger's test did not detect publication bias.

Conclusion

The findings suggest that highest 25[OH]D concentration is correlated with elevated risk of prostate cancer and a modest dose-response effect exists in this association; however, more studies are needed.

Identification of low oxygen-tolerating bacteria in prostate secretions of cancer patients and discussion of possible aetiological significance

The microaerophylic organism Propionibacterium acnes has shown consistent association with prostate cancer (PC). Studies linking circumcision with reduced PC further support anaerobes involvement as circumcision reduces anaerobe colonisation on the glans penis. A 1988 study linked anaerobes with PC but considered them as opportunists in necrotic tumour. A hypothesis that a “Helicobacter-like” process causes PC justified this pilot study. Active surveillance patients were enrolled. Post-prostate massage urine samples were screened using the Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) technique for bacterial identification after culture in anaerobic and aerobic conditions. 8 out of 18 patients (41%) had either obligate anaerobic (n = 5) or microaerophilic (n = 4, one of whom also had anaerobes) organisms identified. None of 10 control samples contained obligate anaerobes. Although mean PSA was 63% higher in those with low oxygen tolerating bacteria, two high outliers resulted in this difference being non-significant. Given the substantially higher proportion of PC patients with organisms growing in a low concentration of oxygen when combined with previous studies compared to controls, the degree of significance was as high as smoking 5–9 cigarettes a day and needs further investigation. Translational research in trials combining Vitamin D and aspirin have begun as part of such investigation.

Relative importance of summer sun exposure, vitamin D intake, and genes to vitamin D status in Dutch older adults: The B-PROOF study

BACKGROUND/OBJECTIVES

The prevalence of vitamin D deficiency among seniors is high. Whereas sun exposure, vitamin D intake, genes, demographics, and lifestyle have been identified as being important determinants of vitamin D status, the impact of these factors is expected to differ across populations. To improve current prevention and treatment strategies, this study aimed to explore the main determinants of vitamin D status and its relative importance in a population of community-dwelling Dutch older adults.

METHODS/SUBJECTS

Serum 25-hydroxyvitamin D (25(OH)D) was measured in 2857 adults aged ≥65 years. Sun exposure was assessed with a structured questionnaire (n=1012), vitamin D intake using a Food Frequency Questionnaire (n=596), and data on genetic variation that may affect 25(OH)D status was obtained for 4 genes, DHCR7 (rs12785878), CYP2R1 (rs10741657), GC (rs2282679), and CYP24A1 (rs6013897) (n=2530).

RESULTS

Serum 25(OH)D concentrations <50nmol/L were observed in 45% of the population; only 6% of these participants used vitamin D supplements. Sun exposure (being outside daily during summer: 66±25nmol/L vs not being outside daily during summer: 58±27nmol/L, P=0.02) and vitamin D intake (per unit μg/day during winter/spring: 3.1±0.75nmol/L, P<0.0001) were associated with higher 25(OH)D concentrations. Major allele carriers of SNPs related to DHCR7, CYP24A1, and GC, as well as CYP2R1 minor allele carriers had the highest 25(OH)D concentrations. Together, sun (R²=0.29), vitamin D intake (R²=0.24), and genes (R²=0.28) explained 35% (R²=0.35) of the variation in 25(OH)D concentrations during summer/autumn period, when adjusted for age, sex, BMI, education, alcohol consumption, smoking, physical activity, and self-rated health status (n=185).

CONCLUSION

The investigated determinants explained 35% of 25(OH)D status. Of the three main determinants under study, sun exposure still appeared to be an important determinant of serum 25(OH)D in older individuals, closely followed by genes, and vitamin D intake. Given the low frequency of vitamin D supplement use in this population, promoting supplement use may be an inexpensive, easy, and effective strategy to fight vitamin D deficiency.

Tightrope Walking: Using Predictors of 25(OH)D Concentration Based on Multivariable Linear Regression to Infer Associations with Health Risks

The debate on the causal association between vitamin D status, measured as serum concentration of 25-hydroxyvitamin D (25[OH]D), and various health outcomes warrants investigation in large-scale health surveys. Measuring the 25(OH)D concentration for each participant is not always feasible, because of the logistics of blood collection and the costs of vitamin D testing. To address this problem, past research has used predicted 25(OH)D concentration, based on multivariable linear regression, as a proxy for unmeasured vitamin D status. We restate this approach in a mathematical framework, to deduce its possible pitfalls. Monte Carlo simulation and real data from the National Health and Nutrition Examination Survey 2005-06 are used to confirm the deductions. The results indicate that variables that are used in the prediction model (for 25[OH]D concentration) but not in the model for the health outcome (called instrumental variables), play an essential role in the identification of an effect. Such variables should be unrelated to the health outcome other than through vitamin D; otherwise the estimate of interest will be biased. The approach of predicted 25(OH)D concentration derived from multivariable linear regression may be valid. However, careful verification that the instrumental variables are unrelated to the health outcome is required.

Baseline serum 25-hydroxyvitamin d levels in men undergoing radical prostatectomy: is there an association with adverse pathologic features?

INTRODUCTION/BACKGROUND

The purpose of this study was to evaluate the prevalence of vitamin D (VitD) deficiency in men undergoing radical prostatectomy and determine whether an association exists between preoperative VitD levels and adverse pathologic features.

PATIENTS AND METHODS

Patients scheduled to undergo radical prostatectomy for clinically localized disease from January to August 2012 were prospectively followed and those with available preoperative serum 25-hydroxyvitamin D levels were included. Men with a known diagnosis of VitD deficiency or taking VitD supplementation were excluded. Cox regression analysis was performed to determine whether preoperative VitD level is predictive of adverse pathologic outcomes.

RESULTS

One hundred consecutive men were included. Mean age was 62 (range, 42-79) years and mean VitD level was 26 (range, 6-57) ng/mL. Overall, 65 men (65%) had suboptimal levels of VitD (< 30 ng/mL), and 32 (32%) had deficiency (< 20 ng/mL). There was no significant correlation between VitD and age (P = .5). In logistic regression analysis, VitD level was not predictive of pathologic Gleason (P = .11), pathologic stage (P = .7), or positive margin status (P = .8).

CONCLUSION

The association between VitD and prostate cancer has been controversial and data suggesting an increased risk of aggressive cancer in men with low levels of VitD have been inconsistent. We found that baseline preoperative VitD level was not associated with any adverse pathologic features. However, VitD deficiency is a common finding in this population, although unrelated to patient age. These results represent the first time the correlation between VitD and prostate cancer has been evaluated in a cohort of men undergoing radical prostatectomy.

Predicting vitamin D deficiency in older Australian adults

OBJECTIVE

There has been a dramatic increase in vitamin D testing in Australia in recent years, prompting calls for targeted testing. We sought to develop a model to identify people most at risk of vitamin D deficiency.

DESIGN AND PARTICIPANTS

This is a cross-sectional study of 644 60- to 84-year-old participants, 95% of whom were Caucasian, who took part in a pilot randomized controlled trial of vitamin D supplementation.

MEASUREMENTS

Baseline 25(OH)D was measured using the Diasorin Liaison platform. Vitamin D insufficiency and deficiency were defined using 50 and 25 nmol/l as cut-points, respectively. A questionnaire was used to obtain information on demographic characteristics and lifestyle factors. We used multivariate logistic regression to predict low vitamin D and calculated the net benefit of using the model compared with 'test-all' and 'test-none' strategies.

RESULTS

The mean serum 25(OH)D was 42 (SD 14) nmol/1. Seventy-five per cent of participants were vitamin D insufficient and 10% deficient. Serum 25(OH)D was positively correlated with time outdoors, physical activity, vitamin D intake and ambient UVR, and inversely correlated with age, BMI and poor self-reported health status. These predictors explained approximately 21% of the variance in serum 25(OH)D. The area under the ROC curve predicting vitamin D deficiency was 0·82. Net benefit for the prediction model was higher than that for the 'test-all' strategy at all probability thresholds and higher than the 'test-none' strategy for probabilities up to 60%.

CONCLUSION

Our model could predict vitamin D deficiency with reasonable accuracy, but it needs to be validated in other populations before being implemented.

Dietary, lifestyle, and genetic determinants of vitamin D status: a cross-sectional analysis from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Germany study

PURPOSE

Considerable variation in 25-hydroxyvitamin D (25(OH)D) in populations worldwide that seems to be independent of latitude has been reported. Therefore, we aimed to assess vitamin D status of a mid-aged German general population and to identify its dietary, lifestyle, anthropometric, and genetic determinants.

METHODS

25(OH)D concentrations were measured by LC-MS/MS in plasma samples of a random subcohort of the German arm of the European Prospective Investigation into Cancer and Nutrition (EPIC) comprising 2,100 subjects aged 35-65 years. Associations between potential predictors and 25(OH)D were assessed by linear regression models.

RESULTS

32.8% of the variance in 25(OH)D was explained by a multivariable regression model, with season being the by far strongest predictor (semi-partial R²: 14.6%). Sex, waist circumference, leisure time physical activity, smoking, polymorphisms in the GC, CYP2R1, and DHCR7 genes, supplement use, exogenous hormone use, alcohol consumption, egg consumption, and fish consumption were significantly associated with 25(OH)D concentrations as well. However, none of these factors explained >2.3% of the variance in 25(OH)D.

CONCLUSION

Even with a comprehensive set of genetic, anthropometric, dietary, and lifestyle correlates, not more than 32.8% of the variation in 25(OH)D could be explained in the EPIC-Germany study, implying that vitamin D prediction scores may not provide an appropriate proxy for measured 25(OH)D. Food intake was only a weak predictor of 25(OH)D concentrations, while a strong seasonal fluctuation in 25(OH)D was shown.

Vitamin D and breast cancer: emerging concepts

The benefit of vitamin D in cancer prevention and to certain extent therapy has been well recognized. The active form of vitamin D, 1,25-dihydroxycholecalciferol (1,25(OH)2 D3) is a natural ligand for vitamin D receptor (VDR). Since 1,25(OH)2D3 exerts toxic effects at a concentration that is beneficial, nearly 1500 analogs of vitamin D have been synthesized and evaluated for their efficacy in a variety of carcinogenesis and human cancer models both in vitro and in vivo. Among these only a handful of them have been approved for evaluation in clinical trials for leukemia, breast, prostate and colon cancers. The mechanism of vitamin D action is mediated by the nuclear VDR and the signaling cascade for its action is extensively reported. In this review we focus on the newer concepts for vitamin D action. These include (1) differential effects of vitamin D in maintaining cell proliferation when the cells are under stress but suppressing cell growth when the cells are transformed; (2) functional significance of VDR polymorphism in potential vitamin D responsiveness; (3) regulation of constitutive splicing of vitamin D target gene, CYP24a, by the hormone and its significance; and (4) regulation of microRNA by vitamin D in breast cancer. It is anticipated that the new work in these selective areas would expand the understanding of vitamin D in breast cancer prevention and therapy.